This invention relates generally to a security entry system to prevent unauthorized entry through an inwardly opening door, and specifically to a key-operated tumbler lock having a shaft and cable used to raise (or lower) a doorstop mounted on an inwardly swinging door, preventing opening of the door whenever the doorstop is down.
It is well known to employ a conventional key actuated tumbler type lock in conjunction with a bolt to prevent unauthorized access into a room through an inwardly opening door. In fact, many devices have been suggested and tried to achieve a burglar-proof entry system for doors. One of the problems with the conventional, key operated tumbler locks is that the lock is subject to "picking" by someone of skill that results in opening the lock and moving the bolt without the proper key. Another problem, is that often the lock bolt itself can be moved to an unlocked position by a thin plastic sheet thrust into the door jamb bolt area or by prying the door jamb with a crowbar or the like, in either case allowing circumvention of the lock. Even a deadbolt lock bolt can be pryed open with a sufficient tool to allow unauthorized entry through a door.
The present invention overcomes the deficiencies of the prior art by providing a key-actuated doorstop security system that prevents unauthorized opening of a door, "picking" of the doorstop actuating lock or any unauthorized entry through an inwardly opening door which could be caused by prying open the door bolt from the jamb. With the use of the present invention, a doorstop engages the floor surface at all times when the door is to remain inaccessable, thus keeping the door closed regardless of conditions of the door bolt or jamb. Only the proper key in conjunction with the tumbler lock provided will also access through the door, since the proper key is the only means for lifting the doorstop from the door outside.